DESCRIPTION (Applicant's abstract): The overall scientific objectives of this proposal are to identify genes whose expression changes as a consequence of two types of sensorineural deafness in the mouse: age-related hearing loss in strain C57BL6/J, and congenital deafness in three deafness mouse mutants. These mutants are being studied at the University of Michigan by two of the co-investigators on this grant. Shaker-2 has been shown to carry mutations in the gene for an unconventional myosin, MyoXV, by Dr. Camper's group. Pirouette and spinner mutants have been mapped and the mutated genes are being identified by Dr. Kohrman's group. We propose to determine the broad effects on the transcriptional repertoire (transcriptome) of the inner ear due to single gene mutations that result in deafness in the mouse. This approach is based on two related hypotheses: (1) these mutations alter the normal developmental processes and homeostatic mechanisms that operate during maturation of the cochlea or in the adult organism, and (2), the alterations will be reflected in changes in the steady state transcript levels of genes that operate in the relevant developmental and homeostatic pathways. By using highly parallel methods to identify gene expression changes, we will begin to characterize the regulatory circuits that are affected directly or indirectly by the mutations, and which themselves may also play critical roles in normal inner ear development, homeostasis and function. Aims 1 and 2 propose to use currently available reagents and technique, such as gene arrays on nylon membranes, to examine gene expression changes in C57BL/6J, a mouse model of age-related hearing loss (Aim 1), and in the three mouse models of congenital deafness and vestibular dysfunction (Aim 2). The final two Aims address the feasibility of applying new and emerging techniques to increase the 'completeness' of the pool of profiled inner ear genes (Aim 3) through database comparisons and SAGE analysis, and the 'throughput' of expression profiling by developing DNA microarrays on glass slides containing genes expressed in the mouse inner ear (Aim 4). These studies should enhance our understanding of the molecular events of age-related hearing loss and congenital deafness and provide new reagents for assessing changes in gene expression in the ear.